The present invention relates to a data switch.
Portable devices such as notebooks, personal digital assistants (PDA), and mobile phones are usually designed to operate in multiple networking environments. For example, a notebook usually has multiple means of connecting to a network. Depending on the environment, the user of the notebook may opt to connect to a network wirelessly, using IEEE 802.11 or HomeRF wireless communication standard. The user may also opt to connect to the network using a more secure connection such as a direct wire connection to a local area network (LAN) using an unshielded twisted pair (UTP) cable terminated with a RJ-45 plug (RJ-45 Cable), for example.
To enable connection flexibility and portability, notebooks must be designed with the ability to switch from one type of network connection to another, such as from a wireless connection to a wire connection, or from one network communication port to another network communication port. Notebooks typically have multiple network communication ports such as an 802.11 wireless communication port, a RJ-45 compatible network port, and a docking station network port. Conventionally, a notebook is switched to operate with the RJ-45 network port or the docking station port by using an off-chip local area network (LAN) switch or an off-chip high speed analog multiplexer, which is located between the output of the notebook's physical layer device (PHY) and the RJ-45 and docking station ports. In other words, the LAN switch is separate and distinct from the PHY chip. Although the example above relates to notebooks, other types of devices (e.g., desktop and other portable devices) with networking ability may encounter the same issues.
This extra hardware between the notebook's PHY and the network communication ports is disadvantageous for several reasons, including: added cost of additional components; increased overall power requirements because of the extra components and higher PHY power that is needed to offset transmit amplitude loss; and reduced cable reach and link performance due to hybrid mismatch and signal distortions. Accordingly, what is needed is a gigabit controller without the above disadvantages.